Arc extinguishing chamber



2 Sheets-Sheet 1 Filed June 7, 1954 INVENTOR. ANDR LATOUR ATTORNEY Feb. 26, 1957 A. LATOUR 2,783,336

ARC EXTINGUISHING CHAMBER INVENTOR. AND RE LATOUR AM-k MAM AT TORN E Y United States PatentO ARC EXTINGUISHING CHAMBER Andr Latour, Grenoble, France, assignor to Etablissements Merlin & Gerin, Grenoble, France Application June 7, 1954, Serial No. 434,891

Claims priority, application France June 17, 1953 7 Claims. (Cl. 200-147) The invention is concerned with a device for extinguishing an electrical arc to be drawn between separable contact members. More particularly the invention relates to a development of an arc extinguishing chamber of the type which comprises a set of at least two plates of refractory i'nate rial partitioning the chamber into divisional chambers. The divisional chambers are provided with are subdividing elements, each one shaped with a pair of legs, the legs diverging in V-form relatively to each other. The legs are comparatively short relatively to the height of the chamber. The conductiveelemcnts straddle with their legs the lower edges of the partitioning plates, the legs of opposite elements in each divisional chamber being disposed so as likewise to diverge in ll-form relatively to'each other. The arcthus is drawn as a whole'orin sections into the space or'spaces between the plates, is turned round into a position parallel to'the plates and caused to form a peripherally expanding path within the space or spaces between the plates.

Arc extinguishing chambers of this type I have disclosed in my earlier U. 5. Patent No. 2,668,890 and in my co-pending U. S. patent application Serial No. 360,299, new Patent No. 2,750,476 dated June 12, 1956, and patent application 360,300, new Patent No. 2,707,739, dated May 3, 1955, both filed on June 8, 1953.

it is a primary object of the invention todevelop such an arc extinguishing chamber which is substantially closed around its perimeter except that thereare provided an entrance opening for the conductive elements and, distributed around the circumference, restricted, vgas permeable and are attenuating passages outofthe'divisiojnal chambers.

it is'a' further object or the'invention to make use of the electrodynamic forces inherentto an electricarofor expandingwiz n the chamber the arc,' or within each orient the dirt anal chambers the are sections'to a'nearly closed loop'or a. great'arcus which, on furtherexpansion will bear-s, the peripheral border member which enclosesthe divisional chamber.

ln'accoidaneewith the invention, the peripheral border main ers, which like a frame enclose or border the divisional chambers or the interspaces between adjacent plates of refractory material, substantially close these intersp'aces vith'the following exceptions. Eachborder member is shaped an entranceopening forextending therethrough the legs of the conductiveelementsinto the divisional chambers. The border members arefurther formed with gas permeable, arc attenuating, restricted passages out of the divisional chambers and distributed aioundthe perimeter of thedivisional chambers, These passages are'cxtrerneiy narrow compared with the width of the chamber sections or interspaces.

The border member of the invention will thus have the effect of a flame arr'ester. For enhancing theflame arresting effect, the border member may be provided with an edge projecting'into the chamber space. This flame" arrester' thus, besides presenting to the are a conice siderably increased surface upon which the hot gases are in contact with a cold wall surface, will reduce the thickness of the flame sheet, both effects coming into play, ever according to the arrangement chosen, simul taneously or separately.

This effect may be achieved by approaching the transversal partitions of the are extinguishing chamber closely to one another. it may also be achieved by means of one or more ring or frame-like thin laminae inserted between the transversal refractory plates or partitions and spaced apart from one another and also from the partitions by a narrow distance.

The inventor has discovered, and this forms part of the invention, that this are expanding and extinguishing effect may be utilized for extinguishing the are by means of a porous body. This will be the more readily achieved the closer together and the more numerous the are loops are assembled within a relatively narrow space. Since the conductive elements in alternation with are loops constitute a composite solenoidal path, whose convolutions are individually extended into the divisional chambers and are close together, a great expanding electrodynamic force will be imparted to the loops. The are sections will thus not only hear and be pressed against the lateral border members of the divisional chambers but will also penetrate deeply into the narrow passages so that the attenuaionized gases may easily traverse these border Walls without causing an overpressure which might endanger the plates or might affect their durability. The flame arrester may thus be in the form of a porous enclosure or, with the exception of the entrance opening for the conductive elements, a fully closed but porous Wall. The chamber sections of rectangular arc extinguishing chambers will thus be closed on three sides by three porous border walls which ensure the evacuation of the gases. If the arc extinguishing chamber is circular, it will be closed around its periphery, leaving only the opening for the insertion of the legs of the are conducting elements.

To this purpose, any porous refractory material, natural or synthetic, may be employed which is insulating or semiconductive, or material composed of grains of such insulating or semi-conductive, refractory material. Such material may be quartz, sinelted silica, corundum, zirconia, glucina, magnesia, or the like. The material will preferably be used in pure condition, such as in the form of electrocast magnesia. The material may be recovered or brought into proper grain or particle size by grinding, crushing, or otherwise. The grains may be bound together by any conventional or convenient process, such as by fritting, that is a vitrifying process under such conditions of temperature and pressure that the grains are only imperfectly vitrified. Under the conditions of this process the grains will be fused together only superficially and, particularly, only to such an extent that contiguous or neighboring grains fuse together at their small contacting edges or areas. The grains or the individual grains thus will not be fused down as a whole, and the pores and thus the passages for the gases between the grains will be kept open. 7 Q

The size of the grains may vary between wide limits,

arsaaae thus the grains may be of a size that they pass 0.59 to 0.074 mm. sieve openings, corresponding to sieves Nos. 30 to 200, U. S. standard. The porosity of the material may vary for instance between pore sizes between similar limits, for instance between ,3 0 and 1 mm.

A fritting process will require higher baking temperatures, the temperatures depending upon the specific material employed. Lower moderate temperatures will suffice, for instance of the order of 1000 C. if the grains at their contacting areas are cemented together with the aid of very small quantities, e. g. up to of a fluxing agent whose adhesiveness may be activated or realized already at such moderate temperatures.

Any convenient or conventional fiuxing agent may be employed, such as the aluminous, magnesic, calcic, or alkaline silicates or analogous borates or any other more or less vitrifiable agent. Fluxing agents such as the alkaline salts may also be employed, as known in the art. which are capable of combiningwith the siliceous material of the grains by superficial attack or reaction yielding a vitrified surface layerglass, enamel-which thus binds the grains together.

For holding the grains together in the preliminary stage of the fusing or vitrifying process, water or any one of the conventional organic binders like sugars, glue, gelatine, dextrines, gums, starch, flour, molasses, sulfite waste liquors, and others, may be employed. The material, thus loosely bound together, may then be subjected to a pressure of several hundreds of kilograms per square centimeter at a temperature of about 1000 C. and the grains thus be bound together permanently at the contacting edges or surface areas. 7

In accordance with a further development of the invention, the porous border walls may consist of the refractory products known as cermets, that is products obtained through the processing of a mixture of ceramic pastes, with more or less refractory metals such as titanium, zirconium, thorium, tantalum, tungsten, molybdenum, and others; products which as semiconductors present the advantage that through their semi-conductivity the penetration of the arc loops into the porous wall material will be enhanced. The oxides and carbides of such metals may also be employed in view of their high refractoriness. The are loops will thus, so to say, be absorbed by the lateral walls of the chamber sections.

These and other features and objects of the invention will become apparent as the specific description of the invention proceeds in which the invention will be described with reference to the accompanying drawings which form part of this specification and which by way of example illustrate various embodiments of my invention. These drawings are to be understood explicative of the invention but not limitative of its scope. Other embodiments incorporating the principle underlying my invention are feasible without departing from the spirit and ambit of my appended claims.

In the drawings:

Fig. 1 is a diagrammatic side view of an embodiment of a circuit breaker with an arcing chamber partitioned by transversal refractory plates into divisional chambers, spaced apart and enclosed by peripheral border memers;

2 is a front view and Fig. 3; a side view of an arc subdividing conductive element;

Fig. 4 is an elevational section of a part of a series of partitioning plates, with their are conducting elements and providing narrow passages around, and out of, the divlsional chambers; and

Fig. 7 a median elevational section similar to Fig. 4 of a modified arrangement of the peripheral wall member of the invention.

In Fig. l the fixed and movable contacts of the circuit breaker are designated by 11 and 12. They are respce tively connected to the terminals 13, 14 of the network line. The two contacts are located inside an arc formation chamber 15, not shown here in detail.

In order to develop the ignited are more rapidly than the movement of the movable contact would allow, an arcing contact 16 may be placed within the arc formation chamber of insulating material. The arcing contact 16 may be connected to the movable contact l2. A blowout coil 17, connected to one of the terminals, 13, of the circuit breaker, may also be employed. The coil 17 acts upon the magnetic core 18, the legs 19 which enclose the arc formation chamber.

The upper part of the circuit breaker, above the arc formation chamber 15, constitutes the are extinguishing chamber. Through a set of refractory plates 21, in the instance illustrated, transversely of the contacts 11, 12, 16, the arc extinguishing chamber is partitioned into divisional chambers 22. Arc subdividing conductive elements 23 are interposed between the separable contact members or the main arcing contacts 11, 16. The conductive elements 23 are shaped, as Figs. 2, 3 and 5 illustrate with a pair of legs or Wings 24, 25, diverging in V-form relatively to each other and connected through a bridge piece 26. The conductive elements straddle with their legs and bridge pieces the lower edges of the partitioning plates 21 and reach with their legs, such as 24, 25; 124,125; 224, 225; 324, (Fig. 4), each into two consecutive divisional chambers 22, 122; 122, 222; 222, 322; 322 respectively, terminating at an intermediate point of the divisional chambers, preferably in the lower part thereof, as Figs. 4, 5 and 7 illustrate. Opposite elements, such as 25, 124; 125, 224; in each sectional chamber, 122, 222, respectively, likewise diverge in V-form relatively to each other.

The chamber sections 22 are circumferentially framed or enclosed by border members by means of which, as Fig. 4 illustrates, the plates 21, 121, 221 may be spaced apart from each other. These border members are shaped with an entrance opening 31, Fig. 5, for the legs or Wings 24, 25 of the conductive elements and, moreover, between adjacent partitions and distributed around the divisional chambers, with gas permeable and are attenuating restricted passages out of the divisional chambers.

In the embodiment of Figs. 4 to 6, the border members framing or enclosing the circular divisional chambers comprise a ring 30 as border wall which provides the spacing for the divisional chamber. This ring is open at the lower part, 31, for the introduction into each divisional chamber of the legs of two successive or opposite conductive elements. Between the ring-like walls 30 and the partitioning plate 21, there is inserted at both sides a ringshaped lamina 43 provided with slightly raised spacing ribs 44 between which thus, distributed around the perimeter of the arc extinguishing chamber, fine, axially extremely narrow, radially directed, passages 45, are shaped. These fine passages, while attenuating the arc, allow the escape of the hot gases. To enhance the attenuation of the arc, the ring-like wall 30 is further provided with an inwardly projecting edge.

The border members, besides spacing the refractory plates 21 apart from one another, thus serve as flame arr-esters. Through the obstacle presented by the ringlike wall, the are loops, which are formed between legs 25, 124 125, 224; are prevented from developing to the outside of the arc extinguishing chamber. The are sections are thus compelled, while being expanded under the electrodynamic forces inherent to the arc loops, to reach and bear against the border wall, substantially around the whole periphery thereof, and thereon to enter the narrow gaps between plates and border wall. The

are sections thus are attenuated and cooled at the surfaces of the partitioning plates and the inwardly projecting edge of the bordering wall of the gap. The arc sections will extinguish while, simultaneously, the hot ionized gases developed by the arc loops may escape through the gaps.

The stacked partitioning plates and interposed border members may be held together by any convenient means or framework, here, since not forming part of the invention, not shown.

The conductive elements 23 may be held in position by being seated with their lower edges on projections 36 of the ring-like walls 30, Fig. 5. These conductive elements, instead of being seated on projections 36 of the ring-like walls 30, might however be supported and secured at the stack of refractory plates by any other convenient means.

Instead of separate, passage providing ring-laminae, the passages may also be shaped within the surfaces of the partitioning plates or may be spared out of the surfaces of the ring-like walls 30 or may be provided both in the partitioning plates and the ring-like walls.

In the embodiments illustrated, the partitioning plates are circular discs, and the border members correspondingly of ring form. Partitioning plates and border members may also be rectangular, oblong, elliptic, or of any other shape, as conditions may ever require.

Through the serial arrangement of the subdividing conductive elements in alternation with the arc loops, a composite solenoidal path is constituted, with its convolutions close together and substantially parallel to one another. The are loops are thus subjected to intensive electro dynamic forces which, expand the loops until they reach substantially the whole circumference of the bordering wall member, bear thereagainst and finally are forced to penetrate into and pass through even very fine and narrow passages, such as the pores of a porous refractory wall member.

It is thus even possible to provide in addition to the narrow gaps 33, or even exclusive thereof, wall members of refractory, highly porous material, instead of nonporous refractory material such as asbestos.

Fig. 7 illustrates an embodiment of this type. The ring-like walls 47 join directly the partitioning plates 46 without any openings or passages being provided other than those for the legs of the conductive elements.

The border walls 47 are of highly porous, refractory material, electrically insulating or semi-conductive as described hereinabove. When the arc has been drawn, the arc loops will expand and will finally extinguish through being absorbed by the porous material and cooled on the pore surfaces of very large size relatively to the mass of I material, while the gases escape to the outside through the pores of the material.

I claim:

1. An arc extinguishing chamber of the type which comprises a set of at least two plates of refractory material partitioning the chamber into divisional chambers, are subdividing conductive elements being provided at said chambers, each one of said elements shaped with a pair of legs of a length short relatively to the height of the chambers, said legs diverging in V-form relatively to each other and straddling the lower edges of said partitioning plates, the legs of opposite elements in each divisional chamber being disposed so as to diverge likewise in V- form relatively to each other; said chambers being provided with peripheral border members of a contour generally corresponding to the contour of said partitioning plates; said border members being shaped each with an entrance opening for extending said legs therethrough and into said divisional chambers; said border members being further formed with gas permeable and arc attenuating, 7O

restricted passages out of said divisional chambers, said 6 passages being distributed around the perimeter of said divisional chambers; said border members being otherwise shaped so as to close saE-i divisional chambers around said perimeter.

2. A divisional arc extinguishing chamber as set forth in claim 1 wherein said border members include a wall in the form of a frame-like element disposed between successive partitioning plates for spacing them apart a short distance, said frame-like elements being of a contour generally corresponding to the contour of said partitioning plates; said frame-like elements being shaped with an entrance opening for said legs, said border members further being formed with gas permeable and flame attenuating, narrow passages out of said divisional chambers and distributed around the perimeter thereof.

3. A device as set forth in claim 2 wherein said border members further include ring-shaped laminae disposed on each side of said frame-like element and between the same and the adjacent plate, said laminae being shaped with slightly raised spacer ribs, distributed around the perimeter of said ring-shaped laminae, so as to provide radially directed, extremely fine and narrow passages out of said divisional chambers.

4. Divisional chamber as set forth in claim 1 wherein said partitioning plates and said border members are of circular contour.

5. Divisional chamber as set forth in claim 1 wherein said border members are of highly porous refractory material.

6. Device as set forth in claim 5 wherein said refractory material is composed of a mixture of refractory metal and ceramic material.

7. In an arc extinguishing chamber, a set of parallel plates of refractory material, spaced apart from one another with a short distance therebetween, thereby to partition said arc extinguishing chamber into narrow divisional chambers, said divisional chambers each being provided with conductive elements, each element being shaped with a pair of diverging wings and a bridge piece connecting said wings, said conductive elements straddling with their bridge pieces the lower edges of said partitioning plates and reaching with their wings each into two consecutive chambers, terminating in the lower part thereof, the wings of opposite elements in each chamber likewise diverging in V-form from each other; peripheral border members being disposed circumferentially around said divisional chambers, the contour of said border members generally corresponding to the contour of said partitioning plates; said border members being shaped each with an entrance opening for said wings and with gas permeable and flame attenuating, restricted passages out of said divisional chambers, said passages being distributed around the perimeter of the divisional chambers; thereby, by means of said conductive elements, to develop the arc in sections expanding as loops within said divisional chambers, said conductive elements in alternation with are loops constituting a composite solenoidal path; the convolutions of said solenoidal path, individually extended into said divisional chambers, being substantially close together and parallel each other; for thus expanding, under the action of the electrodynamic forces, the arc sections into nearly closed loops towards the border wall, so as to reach the same and bear there against and finally forcing the arc loops through said restricted passages, attenuating the same thereby, extinguishing them, and releasing the gases.

References Cited in the file of this patent UNITED STATES PATENTS 2,564,178 Strobel Aug. 14, 1951 

